For control of the motion of an industrial robot, there is ordinarily adopted a method in which the arranged industrial robot is manually set at a predetermined standard posture and an aimed position for the motion is calculated by using positions of respective moving elements as reference values. This operation of setting the posture of the robot, that is, the operation of setting the robot at the standard position, is necessary when it is desired to change the set position of the robot or when maintenance of the robot or an exchange of tools is carried out.
Japanese Unexamined Patent Publication No. 60-20878 discloses an apparatus for determining the standard position of an articulated industrial robot. However, this apparatus is defective in that, since the rotation axis of a wrist assembly of the robot is utilized as the object of the measurement, a casing of the wrist must be dismounted for the determination and the operation is troublesome.